'How could he have found us so quickly?' A student has asked if the have found in this sentence is present perfect of past perfect? My feeling is it is past perfect but I don't have an explanation for him. Thanks in advance.

The problem with assigning tense/form labels to modals is that functionally such labels won't always hold true:

I'm sure he will have seen her yesterday. ("Future perfect"?!)
Surely they could have seen us tomorrow instead? ("Past" perfect?!)

The best thing therefore is probably to just call these sorts of constructions modal + perfect, i.e. "modal perfects", and let the exact meaning and function be made clear by the context.

I guess the least I'd do is ensure that the student could form the non-modal Simple past and Present perfect versions, and only perhaps the Past perfect, of the original sentence (How did he find us so quickly?; How has he found us so quickly?; How had he found us so quickly?), and not worry too much about using modal constructions, or at least not worry about what exactly they should be called, whenever possible/avoidable!

"BONUS": One thing I reckon with your example Tessa is that the implicitly "superlative" 'so quickly' is what is probably adding the most perfectivity (compared to say the more "comparatively-oriented" How could [might] he have found us [certainly quicker/more quickly]?, in which the guy ultimately perhaps didn't find us at all, and is therefore needing some help with his searching skills!), though the perfect aspect of 'have found' is undeniably helping in the most straightforward reading. That is, the modal itself isn't really contributing much perfectivity-wise...and certainly not "tense"-wise, because we could equally well say (at the moment of being found at any rate) How can he have found us so quickly?. Anyway, just blathering away a bit here in this final paragraph!

'How could he have found us so quickly?' A student has asked if the have found in this sentence is present perfect of past perfect? My feeling is it is past perfect but I don't have an explanation for him. Thanks in advance.

I think you're question is a nonstarter -- perhaps it was analyzed wrong. "Have" pairs up with "could" (not "found"), and forms the obligatory infinitive expected after a modal. You see, "could have" is the simple past of "could." And "found" is simply its past participle. So it should be unnecessary to try to understand it in terms of present or past perfect.

I think I'll take Taylor's analysis of modals over yours (and perhaps even mine), Jotham!

Taylor, on pp 405-7 of his Cognitive Grammar, wrote:

20.3 Modals

So far in this chapter I have considered the grounding of a clause solely with respect to present vs. past tense of the verb. Prototypically, these 'locate' a situation in present or past time. Another set of grounding elements, in English, are the modals: can, must, might, should, and several more.

The modals share a number of distinctive properties. For example, they do not inflect for past tense,[6] and with a third-person singular subject they do not take the charateristic -s inflection. These seemingly unrelated facts point to the status of modals as grounding elements. The modals do not take the characteristic exponents of grounding (tense inflection and subject-verb agreement) because the modals are themselves grounding elements. To put it another way: tense inflection and subject-verb agreement on the one hand, and modals on the other, are in complementary distribution. If a clause is grounded by one of the devices, it cannot be grounded by the other.

Semantically, the modals offer a special perspective on a situation. A speaker who states Louise walked to the store is committed to the 'actuality' of the situation, whether in 'reality' or in a fictional space. Modals, in contrast, assess a situation with respect to its likelihood. A number of different modalities can be distinguished. The situation 'Louise walk to the store' may be assessed as probable (Louise might walk to the store), as impossible (can't), as necessary (must), as possible (can), and so on.

These different modalities can often be understood in terms of some notion of force (for more discussion, see section 26.2 [mainly Talmy and 'force dynamics' - FH]). The force may be one which impinges on a participant or a state of affairs, rendering the situation necessary (must); the force may prevent a situation from being the case (can't); there may be an absence of force requiring or preventing a situation, hence, something is possible (though not necessary) (can). The 'strength' of the force, and hence also of the modality can vary. Must is a high-strength modal, should is low strength.

[Taylor then briefly discusses how the differences between root/deontic and epistemic modality is to do with the sources and types of the force, but begs off of a detailed analysis before continuing - FH]: Two points however need to be emphasized.

First, the English modals offer a perspective on a process assessed at the time of speaking. If the modality concerns a past-time situation, the modal as such does not appear in a past-tense form. He might be joking presents a speaker's present-time evaluation of the likelihood of a present situation; the force of logic suggests the possible conlusion that 'he is joking'. He might have been joking also presents a speaker's present-time evaluation, but of a past situation. The modal itself (might) remains the same.

[The second point that Taylor makes is that modality can be expressed instead by the use of e.g. adverbials such as probably, and that certain 'modal' expressions such as be able to, be supposed to etc are 'from the point of view of their grounding by tense inflections, perfectly normal verbal expressions' - FH].

[6] It might be argued that could is the past-tense form of can, might the past tense of may, should the past tense of shall, and so on. While it may be true that historically the one set of items were past-tense forms, in the modern language they do not function as such, but rather offer a present-time perspective on a situation.

Thank you, Fluffyhamster, for sharing Taylor's information about modals. It is the most helpful that I've seen. I have had such a tough time over the years explaining modals to my ELL's. I didn't realize that these words are simply not used in the grammatical way I expected. I will have an easier time explaining them to my students by showing that they are used differently in the modal context.
As an aside, my students often use "even" on its own in a sentence where the word "though" is needed (i.e., She came to school even she was sick.). Any ideas on how to explain why we say "even though"?

You're very welcome, mdavis. Although the "standard" word on modals in ELT is likely Lewis still (whose concept of 'remoteness'*, as expounded in his book The English Verb, provides a very useful umbrella term that is able to cover both lexical tense and modality, as shown in the diagram and discussion here: http://forums.eslcafe.com/job/viewtopic.php?p=954436#954436 ), Taylor's words there seemed a reasonably concise way of at least hinting at similar ideas.

'Even though' is synonymous with 'although' (from all + though). You should then compare 'even though/although' with the genuine/correct use of 'even' by itself (i.e. as an adverb rather than as part of a still orthographically-separated subordinator), so the students won't form any wrong ideas or strange aversions: He never even opened the letter (let alone read it); It was cold there even in summer; Even a child can understand it; She didn't even call to say she wasn't coming (let alone come round later and apologize); /Even though she was sick/, //she got up, ate breakfeast, ^ went to school ^//! (The ^ marks the two possible positions for 'even' in this last, invented example; the parts in / / and // // can be reversed. The others examples are from the OALDCE - Google the online version, and for similar ALDs from Longman/LDOCE, Cambridge/CALD, Macmillan/MED, and Merriam-Webster's Learner's). Note how the adverb 'even' usually comes right before whatever item is being stressed/highlighted, whilst the subordinator 'even though/although' can only come at the start of its clause, and is arguably referring more to that clause in its entirety. Remember that's there's also 'even if' (with the 'if' probably the operative word), and that that could have a "habitual" quality in this particular context.

*Apparently first mentioned IIRC by Joos back in the 60s, but fleshed out into rough pedagogical form by Lewis.

Last edited by fluffyhamster on Sun May 27, 2012 3:39 am; edited 6 times in total

Returning to the original question: as the context clearly concerns 'dynamic' (i.e. factual) modality, that is, a here used-and-done ability (rather than epistemic/likelihood, or deontic/obligation, etc), the use of "past tense" (or "present tense" in the case of a verb phrase beginning with 'can' rather than 'could') is OK as a rough shorthand, but the problem then is like I said that it's ultimately a "form" rather than function label and can't always be reliably applied elsewhere.

Wow! Thank you so much for your detailed response! I am looking froward to being able to explain even to my students better.
So modals are quite complicated, I see. I'll need to put a little more time into understanding them in order to explain them better. Your input is very helpful, and comprehensive!

Heh, glad to be of help, mdavis. I was just thinking about that 'usually comes right before whatever item is being stressed/highlighted' - you could even say that it is the 'though' there that is being stressed (i.e. that 'even' needs something following it, in this case an actual subordinator, for those students who incorrectly use only the adverb by itself as a "subordinator". So maybe analogize from the single adverb to the phrasal subordinator). Functionally, 'even though' seems much better sorted to this second-clause-initial position than what would be the slightly stuffy and stilted-sounding 'although', and there must be a reason for ordering the clauses that way rather than the other way around (and perhaps with a different subordinator). (I guess the '(Yes, but) She (still) came to school!' is actually the most important info, and the 'even though she was ill' potentially given info?).

If I might add, I got a copy of Lewis' The English Verb some time ago after one of these discussions. It was really interesting reading, and I even managed to use some of it to explain an alternate "grammar" explanation to my high level students. It's one of the few books I kept when I retired. You might find it interesting yourself.